Effects of vitamin D 3 supplementation on cardiac, muscle, and immune responses after a marathon race: a single-blind, placebo-controlled trial.
Pei-Wei Weng, Josephine Diony Nanda, Yu-Hsiu Chien et al.
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In 30 seconds
This single-blind, placebo-controlled randomised trial examined whether 8 weeks of vitamin D₃ supplementation altered cardiac, muscle, oxidative-stress, and immune responses after a full marathon in 21 amateur runners. Blood biomarkers were assessed from 24 hours before to 24 hours after the race. Both groups showed post-race increases in muscle-damage and cardiac-stress markers. Supplementation was associated with attenuated protein carbonyl responses and lower creatine kinase and creatine kinase-MB levels at 24 hours; immune changes were time-dependent, without significant group-by-time interactions.
Key findings
- Vitamin D₃ was associated with attenuation of protein carbonyls, the only oxidative-stress marker with a significant Group × Time interaction.
- At 24 h post-race, the vitamin D₃ group had lower creatine kinase and creatine kinase-MB levels than the placebo group.
- White blood cell counts, particularly neutrophils, increased after the race in both groups; lymphocyte counts decreased at 0.5 h and 2 h.
Why it matters
Marathon running was followed by measurable cardiac-stress, muscle-damage, oxidative-stress, and immune changes. The findings suggest vitamin D₃ may influence selected biochemical responses during early recovery, but effects were not consistent across oxidative-stress or immune measures. This helps frame supplementation as a possible modifier of specific post-exercise biomarkers rather than evidence of broad protection from exercise-related physiological stress.
What to keep in mind
The trial included only 21 amateur runners, and biomarker follow-up extended only from 24 hours before to 24 hours after the race.